Innerspring assemblies (or “innersprings”) are conventionally formed as a matrix or array of individual springs, such as steel wire coil springs, which are interconnected with ends of the springs being arranged in a common plane to provide a reflexive support surface and structure which can be incorporated into a support system or device such as a mattress or seating furniture. Among the wide variety of different types of innersprings, a common form is made with coiled wire springs which have a generally helical coil body with ends at each end of the helix of the body, the ends formed by one or more turns or bends of wire in a single plane to create a planar end which together with adjacent springs in the array create a planar support surface which can bear a load in compression to varying degrees. The helical coil bodies are formed by turns of wire in a right hand or left hand direction about an axis of the coil, and the ends are necessarily formed by additional turns or bends of the wire in the same direction as the coil body. The termination of the wire at each end of the coil spring, also referred to as the “terminal ends”, are typically located at a periphery of the coil body, and the opposite terminal ends may be located on the same side of the coil body or on opposite sides of the coil body.
In innerspring assemblies of the prior art, coil springs of this type are uniformly oriented with the ends of the coils in common planes as noted, and with the terminal ends of the coils commonly located with respect to the coil bodies. As noted in the prior art, the helical turn of the wire of the coil body causes the coil to lean or displace laterally when compressed, typically toward the inclined transition from the coil body to the planar coil end. In innersprings in which all of the coil springs are commonly oriented, the lateral displacement is also uniform and magnified by multiple interconnected coil springs. The lateral displacement component of an entire innerspring can be countered or resisted by the encapsulation of the innerspring in an envelope or covering material, but the spring force action of such an innerspring will always have this lateral component.
Other prior art innersprings combine different types of coil springs with differing wire turn direction to attempt to counter or cancel lateral displacement tendency. This presents formidable challenges to automated manufacture of innerspring assemblies.